Traditional infusion pumps can incorporate sensors to detect malfunctions in the system, such as occlusions, low battery charge, or an empty infusion reservoir. Since traditional infusion pumps frequently use mechanical drive systems, such as DC motors, solenoids, and gears, they also tend to use electromechanical sensors, including pressure sensors, switches, force sensors, capacitive and piezoelectric-based pressure sensors, and strain gauges. Electro-mechanical sensors can be expensive, complex devices with many components. They can be unreliable, at times, and are not always sensitive. In many cases, the physical parameter being sensed by an electromechanical sensor is indirectly related to the failure mode being detected. For example, some traditional infusion pumps measure the torsion of a DC motor shaft, and must correlate shaft torsion with some other variable of interest. Unfortunately, other factors, such as gear friction and friction encountered by moveable partitions, can affect torsion, making it difficult to distinguish occlusion from normal frictional variations. For reasons such as these, it can be difficult to diagnose failure modes using electro-mechanical sensors, such as those used in traditional infusion pumps.
Accordingly, a need exists for new and/or improved methods and systems for detecting malfunctions in an infusion pump.